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An electrogenerative process for the recovery of gold from cyanide solutions

Yap CY, Mohamed N

Chemosphere, 2007 Apr;67(8):1502-10.
PMID: 17296217

Traditional methods for the recovery of gold from electronic scrap by hydrometallurgy were cyanidation followed by adsorption on activated carbon or cementation onto zinc dust and by electrowinning. In our studies, a static batch electrochemical reactor operating in an electrogenerative mode was used in gold recovery from cyanide solutions. A spontaneous chemical reaction will take place in the reactor and generate an external flow of current. In this present work, a static batch cell with an improved design using three-dimensional cathodes namely porous graphite and reticulated vitreous carbon (RVC) and two-dimensional cathode materials, copper and stainless steel plates were coupled with a zinc anode. The electrogenerative system was demonstrated and the performance of the system using various cathode materials for gold recovery was evaluated. The system resulted in more than 90% gold being recovered within 3h of operation. Activated RVC serves as a superior cathode material having the highest recovery rate with more than 99% of gold being recovered in 1h of operation. The morphology of gold deposits on various cathode materials was also investigated.
Negative effects of nicotine on bone-resorbing cytokines and bone histomorphometric parameters in male rats

Hapidin H, Othman F, Soelaiman IN, Shuid AN, Luke DA, Mohamed N

J. Bone Miner. Metab., 2007;25(2):93-8.
PMID: 17323178

The effects of nicotine administration on bone-resorbing cytokines, cotinine, and bone histomorphometric parameters were studied in 21 Sprague-Dawley male rats. Rats aged 3 months and weighing 250-300 g were divided into three groups. Group 1 was the baseline control (BC), which was killed without treatment. The other two groups were the control group (C) and the nicotine-treated group (N). The N group was treated with nicotine 7 mg/kg body weight and the C group was treated with normal saline only. Treatment was given by intraperitoneal injection for 6 days/week for 4 months. The rats were injected intraperitoneally with calcein 20 mg/kg body weight at day 9 and day 2 before they were killed. ELISA test kits were used to measure the serum interleukin-1 (IL-1), interleukin-6 (IL-6), and cotinine (a metabolite of nicotine) levels at the beginning of the study and upon completion of the study. Histomorphometric analysis was done on the metaphyseal region of the trabecular bone of the left femur by using an image analyzer. Biochemical analysis revealed that nicotine treatment for 4 months significantly increased the serum IL-1, IL-6, and cotinine levels as compared to pretreatment levels. In addition, the serum cotinine level was significantly higher in the N group than in the C group after 4 months treatment. Histomorphometric analysis showed that nicotine significantly decreased the trabecular bone volume (BV/TV), trabecular thickness (Tb.Th), double-labeled surface (dLS/BS), mineralizing surface (MS/BS), mineral appositional rate (MAR), and bone formation rate (BFR/BS), while causing an increase in the single-labeled surface (sLS/BS), osteoclast surface (Oc.S/BS), and eroded surface (ES/BS) as compared to the BC and C groups. In conclusion, treatment with nicotine 7 mg/kg for 4 months was detrimental to bone by causing an increase in the bone resorbing cytokines and cotinine levels. Nicotine also exerted negative effects on the dynamic trabecular histomorphometric parameters.
RP-HPLC method for the quantitative analysis of naturally occurring flavonoids in leaves of Blumea balsamifera DC

Nessa F, Ismail Z, Karupiah S, Mohamed N

J Chromatogr Sci, 2005 Sep;43(8):416-20.
PMID: 16212782

A selective and sensitive reversed-phase (RP) high-performance liquid chromatographic method is developed for the quantitative analysis of five naturally occurring flavonoids of Blumea balsamifera DC, namely dihydroquercetin-7,4'-dimethyl ether (DQDE), blumeatin (BL), quercetin (QN), 5,7,3',5'-tetrahydroxyflavanone (THFE), and dihydroquercetin-4'-methyl ether (DQME). These compounds have been isolated using various chromatographic methods. The five compounds are completely separated within 35 min using an RP C18, Nucleosil column and with an isocratic methanol-0.5% phosphoric acid (50:50, v/v) mobile phase at the flow rate of 0.9 mL/min. The separation of the compounds is monitored at 285 nm using UV detection. Identifications of specific flavonoids are made by comparing their retention times with those of the standards. Reproducibility of the method is good, with coefficients of variation of 1.48% for DQME, 2.25% for THFE, 2.31% for QN, 2.23% for DQDE, and 1.51% for BL. The average recoveries of pure flavonoids upon addition to lyophilized powder and subsequent extraction are 99.8% for DQME, 99.9% for THFE, 100.0% for BL, 100.6% for DQDE, and 97.4% for QN.
Fulltext Iron impregnated activated carbon as an efficient adsorbent for the removal of methylene blue: regeneration and kinetics studies

Shah I, Adnan R, Wan Ngah WS, Mohamed N

PLoS One, 2015;10(4):e0122603.
PMID: 25849291 DOI: 10.1371/journal.pone.0122603

In this study, iron impregnated activated carbon (FeAC) was synthesized following an oxidation and iron impregnation of activated carbon (AC). Both the AC and FeAC were characterized by pHZPC and FTIR spectroscopy. The removal of Methylene Blue (MB) by AC and FeAC was examined under various experimental conditions. The FeAC showed up to 95% (higher than AC) MB removal in the pH range of 7-10. Although the reaction kinetics was pseudo-second order, the overall rate was controlled by a number of processes such as film diffusion, pore diffusion and intraparticle diffusion. The activation energy values for the MB uptake by AC and FeAC (21.79 and 14.82 kJ/mol, respectively) revealed a physisorption process. In the regeneration study, FeAC has shown consistently ≥ 90% MB removal even up to 10 repeated cycles. The reusable characteristic of the spent FeAC improved the practical use of activated carbon and can be a breakthrough for continuous flow system applications where it can work effectively without any significant reduction in its performance.
The effect of heavy metals on nitrogen and oxygen demand removal in constructed wetlands

Lim PE, Tay MG, Mak KY, Mohamed N

Sci Total Environ, 2003 Jan 01;301(1-3):13-21.
PMID: 12493181

The objective of this study is to investigate the respective effects of Zn, Pb and Cd as well as the combined effect of Zn, Pb, Cd and Cu on the removal of nitrogen and oxygen demand in constructed wetlands. Four laboratory-scale gravel-filled subsurface-flow constructed wetland units planted with cattails (Typha latifolia) were operated outdoors and fed with primary-treated domestic wastewater at a constant flow rate of 25 ml/min. After 6 months, three of the wetland units were fed with the same type of wastewater spiked with Zn(II), Pb(II) and Cd(II), respectively, at 20, 5 and 1 mg/l for a further 9 months. The remaining unit was fed with the same type of wastewater spiked with a combination of Zn(II), Pb(II), Cd(II) and Cu(II) at concentrations of 10, 2.5, 0.5 and 5 mg/l, respectively, over the same period. The chemical oxygen demand (COD) and ammoniacal nitrogen (AN) concentrations were monitored at the inlet, outlet and three additional locations along the length of the wetland units to assess the performance of the wetland units at various metal loadings. At the end of the study, all cattail plants were harvested for the determination of total Kjeldahl nitrogen and metal concentrations. The results showed that the COD removal efficiency was practically independent of increasing metal loading or a combination of metal loadings during the duration of the study. In contrast, the AN removal efficiency deteriorated progressively with increasing metal loading. The relative effect of the heavy metals was found to increase in the order: Zn
Fulltext Positive association between metabolic syndrome and bone mineral density among Malaysians

Chin KY, Chan CY, Subramaniam S, Muhammad N, Fairus A, Ng PY, et al.

Int J Med Sci, 2020;17(16):2585-2593.
PMID: 33029101 DOI: 10.7150/ijms.49030

Objectives: Metabolic syndrome (MetS) is a cluster of metabolic abnormalities that elevates the individual risk of cardiovascular diseases. These abnormalities are also known to alter bone remodelling. Therefore, MetS may be associated with osteoporosis. This study aims to determine the association between MetS and its components and bone mineral density (BMD) assessed by dual-energy X-ray absorptiometry (DXA) among Malaysians. Methods: 400 Malaysians aged ≥ 40 years (52.5% women) residing in Klang Valley, Malaysia, were recruited. Subjects' demographic and lifestyle details were collected using a questionnaire, and blood pressure and body anthropometry were measured. Subjects' lumbar spine and total hip BMD were measured by DXA. Their fasting blood was collected for blood glucose level and lipid profile analysis. Regression analysis was used to analyze the relationship between MetS or its components and BMD. Results: Subjects with MetS had higher BMD compared to subjects without MetS in models unadjusted for BMI (spine p=0.008; hip p<0.001). This difference was attenuated with BMI adjustment (spine p=0.625; hip p=0.478). Waist circumference was associated positively with BMD in models unadjusted for BMI (spine p=0.012; hip p<0.001), but the association became negative with BMI adjustment (spine p=0.044; hip p=0.021). Systolic blood pressure was associated positively with total hip BMD (p=0.019) but BMI adjustment attenuated the relationship (p=0.080). Triglyceride level was associated with osteoporosis in a fully adjusted model (p=0.001). Overall, MetS was associated with osteoporosis (p=0.019) but lifestyle (p=0.188) and BMI adjustment attenuated the relationship (p=0.904). Conclusion: MetS is positively associated with BMD, and this relationship is predominantly mediated by BMI. Although MetS is not a significant risk factor for osteoporosis, the inverse relationship between waist circumference, a marker of central obesity, and BMD highlights the need to prevent adiposity to improve metabolic and skeletal health.
Comparative anti-osteoporotic properties of the leaves and roots of Marantodes pumilum var. alata in postmenopausal rat model

Giaze TR, Shuid AN, Soelaiman IN, Muhammad N, Jamal JA, Fauzi MB, et al.

J Tradit Complement Med, 2019 Oct;9(4):393-400.
PMID: 31453136 DOI: 10.1016/j.jtcme.2019.01.002

Background: Marantodes pumilum var. alata (MPva), popularly known as Kacip Fatimah, is widely used to maintain female reproductive health, facilitate post-partum recovery and manage symptoms of menopause and osteoporosis in South-East Asia. This study aims to further evaluate the osteoprotective potential of MPva in view of reports of its bone-protective properties in postmenopausal condition.
Methods: Thirty female Sprague-Dawley rats were sorted into 5 groups (n = 6) namely: MPv (leaf treatment); MPr (root treatment); ERT (estrogen treatment); OVXC (untreated ovariectomized control) and Sham (untreated sham-operated control). All rats (except the Sham) were ovariectomized to induce a state of estrogen deficiency that simulates menopause. Two weeks after ovariectomy, the rats were treated for 8 weeks with oral gavages of estrogen and plant extracts. The ERT group received 64.5 μg/kg/day dose of estrogen while MPv and MPr groups received 20 mg/kg/day dose of leaf and root extracts, respectively. At the end of treatment, left femora were excised from euthanized rats and investigated for changes in bone micro-architecture, mineral density, and biomechanical properties.
Results: Bone volume fraction, degree of anisotropy and structure-model-index of bone were significantly improved (p 
An ecological study of the relationship between urban built environment and cardiovascular hospital admissions (2004-2016) in an Asian developing country

Kwan SC, Ismail R, Ismail NH, Mohamed N

Soc Sci Med, 2021 05;276:113868.
PMID: 33799201 DOI: 10.1016/j.socscimed.2021.113868

This study aims to evaluate the relationship between urban built environment and hospital admissions from cardiovascular diseases in Kuala Lumpur, Malaysia. Hospital admission data from 2004 to 2016 for cardiovascular diseases were used with patient residential postcodes as the unit of analysis. Data was split into 2004-2009 (12,551 cases) and 2010-2016 (17,154 cases) periods corresponding to land use data. We used generalized linear mixed model to analyse population density, property value, entropy index, and the kernel density (800 m) of specific land use, bus and rail stations, and road junctions, with time period and postcodes as the random effects to generate incidence rate ratios (IRRs). Results indicated that entropy index and recreational area density were associated with fewer hypertensive disease and ischemic heart disease hospital admissions (IRR range: 0.49-0.68, 95%CI: 0.27, 0.97). Population density and property value were associated with fewer cerebrovascular disease hospital admissions (IRR range: 0.29-0.34, 95%CI: 0.11, 0.75). Contrarily, density of road junctions was associated with 2.5-6.3 times more hospital admissions for cardiovascular disease hospital admissions (IRR range: 2.53-6.34, 95%CI: 1.07,17.91). There were no significant association between hospital admission and density of residential area, undeveloped land, rail and bus stations. The shapes of relationships for all attributes were non-linear, and changed markedly at the third quartile except for recreational area density. The findings suggest that land use attributes have some protective effects on the cardiovascular disease admission cases as compared to the transport attributes. These findings have important merits for integrating health into urban planning.
Fulltext Vitamin E improved bone strength and bone minerals in male rats given alcohol

Zakaria S, Mat-Husain SZ, Ying-Hwey K, Xin-Kai K, Mohd-Badawi A, Abd-Ghani NA, et al.

Iran J Basic Med Sci, 2017 Dec;20(12):1360-1367.
PMID: 29238472 DOI: 10.22038/IJBMS.2017.9610

Objectives: Alcohol consumption induces oxidative stress on bone, which in turn increases the risk of osteoporosis. This study determined the effects of vitamin E on bone strength and bone mineral content in alcohol-induced osteoporotic rats.
Materials and Methods: Three months old Sprague Dawley male rats were randomly divided into 5 groups: (I) control group; (II) alcohol (3g/kg) + normal saline; (III) alcohol (3g/kg) + olive oil; (IV) alcohol (3g/kg) + alpha-tocopherol (60mg/kg) and (V) alcohol (3g/kg) + palm vitamin E (60mg/kg). The treatment lasted for three months. Following sacrifice, the right tibia was subjected to bone biomechanical test while the lumbar (fourth and fifth lumbar) and left tibia bones were harvested for bone mineral measurement.
Results: Alcohol caused reduction in bone biomechanical parameters (maximum force, ultimate stress, yield stress and Young's modulus) and bone minerals (bone calcium and magnesium) compared to control group (P<0.05). Palm vitamin E was able to improve bone biomechanical parameters by increasing the maximum force, ultimate stress and Young's modulus (P<0.05) while alpha-tocopherol was not able to. Both alpha-tocopherol and palm vitamin E were able to significantly increase tibia calcium and magnesium content while only alpha-tocopherol caused significant increase in lumbar calcium content (P<0.05).
Conclusion: Both palm vitamin E and alpha-tocopherol improved bone mineral content which was reduced by alcohol. However, only palm vitamin E was able to improve bone strength in alcohol treated rats.
Fulltext Cost analysis of facial injury treatment in two university hospitals in Malaysia: a prospective study

Saperi BS, Ramli R, Ahmed Z, Muhd Nur A, Ibrahim MI, Rashdi MF, et al.

Clinicoecon Outcomes Res, 2017;9:107-113.
PMID: 28223831 DOI: 10.2147/CEOR.S119910

OBJECTIVE: Facial injury (FI) may occur in isolation or in association with injuries to other parts of the body (facial and other injury [FOI]). The objective of this study was to determine the direct treatment costs incurred during the management of facial trauma.
MATERIALS AND METHODS: A prospective cohort study on treatment cost for FIs and FOIs due to road-traffic crashes in two university hospitals in Malaysia was conducted from July 2010 to June 2011. The patients were recruited from emergency departments and reviewed after 6 months from the date of initial treatment. Direct cost analysis, comparison of cost and length of hospital stay, and Injury Severity Score (ISS) were performed.
RESULTS: A total of 190 patients were enrolled in the study, of whom 83 (43.7%) had FI only, and 107 (56.3%) had FOI. The mean ISS was 5.4. The mean length of stay and costs for patients with FI only were 5.8 days with a total cost of US$1,261.96, whereas patients with FOI were admitted for 7.8 days with a total cost of US$1,716.47. Costs doubled if the treatment was performed under general anesthesia compared to local anesthesia.
CONCLUSION: Treatment of FI and FOI imposes a financial burden on the health care system in Malaysia.
Comparing the performance of body mass index, waist circumference and waist-to-height ratio in predicting Malaysians with excess adiposity

Low NY, Chan CY, Subramaniam S, Chin KY, Ima Nirwana S, Muhammad N, et al.

Ann Hum Biol, 2022 Dec;49(7-8):299-304.
PMID: 36373795 DOI: 10.1080/03014460.2022.2147585

BACKGROUND: Body mass index (BMI) is a widely used surrogate tool to screen for obesity/adiposity, but it cannot differentiate between lean and fat mass. Thus, alternative tools to detect excess adiposity should be identified.
AIM: This study aimed to compare the performance of BMI, waist circumference (WC) and waist-to-height ratio (WtHR) in predicting Malaysians with excess body fat defined by dual-energy X-ray absorptiometry (DXA).
SUBJECTS AND METHODS: A total of 399 men and women aged ≥40 years were recruited from Klang Valley, Malaysia. The body composition of the subjects, including body fat percentage, was measured by DXA. The weight, height, WC and WHtR of the subjects were also determined.
RESULTS: BMI [sensitivity = 55.7%, specificity = 86.1%, area under curve (AUC) = 0.709] and WC (sensitivity = 62.7%, specificity = 90.3%, AUC = 0.765) performed moderately in predicting excess adiposity. Their performance and sensitivity improved with lower cut-off values. The performance of WHtR (sensitivity = 96.6%, specificity = 36.1, AUC = 0.664) was optimal at the standard cut-off value and no modification was required.
CONCLUSION: The performance of WC in identifying excess adiposity was greater than BMI and WHtR based on AUC values. Modification of cut-off values for BMI and WC could improve their performance and should be considered by healthcare providers in screening individuals with excess adiposity.
Comparison of Cytokine Profile between Postmenopausal Women with and Without Osteoporosis - A Case-Control Study

Soh GT, Mohammad AH, Syed Isa SNL, Chin KY, Mohamed N

Endocr Metab Immune Disord Drug Targets, 2023;23(6):811-817.
PMID: 36380416 DOI: 10.2174/1871530323666221114111029

BACKGROUND: Chronic low-grade inflammation is involved in the pathogenesis of postmenopausal osteoporosis, but the cytokines implicated remain elusive.
OBJECTIVE: This study aimed to compare the difference in cytokine profile between postmenopausal women with and without osteoporosis in Klang Valley, Malaysia.
METHODS: Postmenopausal women with (n = 20) and without osteoporosis (n = 20) were recruited for this study. Their bone health status was determined using dual-energy X-ray absorptiometry. Their fasting blood was collected for proteomic analysis. A protein array was performed for four subjects randomly selected from each group to screen the potential cytokines. Three cytokines at least 20% different between groups and consistently expressed by each subject were selected for validation using enzyme-linked immunosorbent assays (ELISA).
RESULTS: The protein array screening demonstrated that platelet-derived growth factor-BB, interleukin- 6 receptor (IL-6R), and tissue inhibitor of metallopeptidase-2 were higher in women with osteoporosis than women without osteoporosis (n = 4 per group), and consistently expressed by all women. Only body mass index (BMI)-adjusted logarithmically transformed IL-6R levels were lower among postmenopausal women with osteoporosis compared to women with normal bone health (p = 0.026) (n = 16 per group) in the ELISA test.
CONCLUSION: IL-6R was lower among postmenopausal women with osteoporosis compared to women with normal bone health after adjusting for BMI. However, a large-scale epidemiological study with proteomic analysis needs to confirm the findings.
Fulltext Levels of Knowledge, Beliefs, and Practices Regarding Osteoporosis and the Associations with Bone Mineral Density among Populations More Than 40 Years Old in Malaysia

Chan CY, Subramaniam S, Chin KY, Ima-Nirwana S, Muhammad N, Fairus A, et al.

Int J Environ Res Public Health, 2019 Oct 25;16(21).
PMID: 31731507 DOI: 10.3390/ijerph16214115

Osteoporosis is a skeletal disorder commonly found among the elderly, in which the bones become weak, brittle, and more susceptible to fracture. Adequate knowledge and positive attitude towards the disease and osteoprotective activities may prevent osteoporosis, but comprehensive studies to verify this hypothesis are limited in Malaysia. This study aims to bridge the research gap by determining the levels of knowledge, beliefs, and practices regarding osteoporosis and their associations with bone mineral density (BMD) among men and women ≥ 40 years in Klang Valley, Malaysia. In this cross-sectional study, 786 Malaysians (382 men, 404 women) completed a questionnaire on knowledge, beliefs, and osteoprotective practices, and underwent BMD scan using a dual-energy X-ray absorptiometry device. The current study found moderate levels of knowledge and beliefs regarding osteoporosis but poor osteoprotective practices. Osteoporosis knowledge, beliefs, and practices were significantly different based on subjects' demographic characteristics (p < 0.05). Osteoporosis knowledge and beliefs were correlated significantly with osteoprotective practices (p < 0.05). Bone health status of the subjects was associated positively with calcium supplement intake, and negatively with exercise barriers and smoking status of the subjects (p < 0.05). However, no significant correlation was noted between osteoporosis knowledge and bone health (p > 0.05). Conclusively, despite some correlations between individual components, the detachment between bone health knowledge and beliefs, and osteoprotective practices among Malaysians is apparent. Integrating all three components into a comprehensive osteoporosis prevention program is warranted.
Fulltext Milled Crown on Post Crack Tooth Syndrome as the Denture Abutment Tooth: A Case Report

Mahalil Amin SS, Keat Hon JC, Sabarudin MA, Wan Ali WNS, Mohamed N

Cureus, 2023 May;15(5):e39380.
PMID: 37362455 DOI: 10.7759/cureus.39380

This clinical case describes using a milled crown on a cracked tooth as the abutment for a removable partial denture. A 63-year-old male patient diagnosed with lipoma undergoing chemotherapy and radiotherapy presented with symptomatic crack tooth syndrome on tooth 36 and partial edentulism. Conservative treatment using a molar band to extracoronally splint the tooth was conducted to determine the prognosis of the crack line. A lower partial cobalt-chromium denture was constructed by incorporating the milled crown of tooth 36 as the abutment. After six months of follow-up, there were no crack tooth symptoms, and regular review was adopted to monitor the tooth. The construction of a milled crown of a cracked tooth presented good and promising clinical outcomes in preserving tooth vitality and preventing crack propagation in partially dentate dentition for the long term.
Fulltext Effect of a Screening and Education Programme on Knowledge, Beliefs, and Practices Regarding Osteoporosis among Malaysians

Chan CY, Subramaniam S, Chin KY, Ima-Nirwana S, Muhammad N, Fairus A, et al.

Int J Environ Res Public Health, 2022 May 17;19(10).
PMID: 35627609 DOI: 10.3390/ijerph19106072

Background: Osteoporosis is an emerging geriatric condition with high morbidity and healthcare cost in developing nations experiencing rapid population ageing. Thus, identifying strategies to prevent osteoporosis is critical in safeguarding skeletal health. This study aimed to evaluate the effects of a bone health screening and education programme on knowledge, beliefs, and practice regarding osteoporosis among Malaysians aged 40 years and above. Methods: A longitudinal study was conducted from April 2018 to August 2019. During the first phase of the study, 400 Malaysians (190 men, 210 women) aged ≥ 40 years were recruited in Klang Valley, Malaysia. Information on subjects’ demography, medical history, knowledge, and beliefs regarding osteoporosis, physical activity status, and dietary and lifestyle practices were obtained. Subjects also underwent body anthropometry measurement and bone mineral density scan (hip and lumbar spine) using a dual-energy X-ray absorptiometry device. Six months after the first screening, similar investigations were carried out on the subjects. Results: During the follow-up session, 72 subjects were lost to follow up. Most of them were younger subjects with a lower awareness of healthy practices. A significant increase in knowledge, beliefs (p < 0.05), calcium supplement intake (p < 0.001), and dietary calcium intake (p = 0.036) and a reduction in coffee intake (p < 0.001) were found among subjects who attended the follow-up. In this study, the percentage of successful referrals was 41.86%. Subjects with osteoporosis were mostly prescribed alendronate plus vitamin D3 by medical doctors, and they followed the prescribed treatment accordingly. Conclusions: The bone health screening and education programmes in this study are effective in changing knowledge, beliefs, and practice regarding osteoporosis. The information is pertinent to policymakers in planning strategies to prevent osteoporosis and its associated problems among the middle-aged and elderly population in Malaysia. Nevertheless, a more comprehensive bone health education program that includes long-term monitoring and consultation is needed to halt the progression of bone loss.
Modeling of Machine Learning-Based Extreme Value Theory in Stock Investment Risk Prediction: A Systematic Literature Review

Melina M, Sukono, Napitupulu H, Mohamed N

Big Data, 2024 Jan 17.
PMID: 38232710 DOI: 10.1089/big.2023.0004

The stock market is heavily influenced by global sentiment, which is full of uncertainty and is characterized by extreme values and linear and nonlinear variables. High-frequency data generally refer to data that are collected at a very fast rate based on days, hours, minutes, and even seconds. Stock prices fluctuate rapidly and even at extremes along with changes in the variables that affect stock fluctuations. Research on investment risk estimation in the stock market that can identify extreme values is nonlinear, reliable in multivariate cases, and uses high-frequency data that are very important. The extreme value theory (EVT) approach can detect extreme values. This method is reliable in univariate cases and very complicated in multivariate cases. The purpose of this research was to collect, characterize, and analyze the investment risk estimation literature to identify research gaps. The literature used was selected by applying the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and sourced from Sciencedirect.com and Scopus databases. A total of 1107 articles were produced from the search at the identification stage, reduced to 236 in the eligibility stage, and 90 articles in the included studies set. The bibliometric networks were visualized using the VOSviewer software, and the main keyword used as the search criteria is "VaR." The visualization showed that EVT, the Generalized Autoregressive Conditional Heteroskedasticity (GARCH) models, and historical simulation are models often used to estimate the investment risk; the application of the machine learning (ML)-based investment risk estimation model is low. There has been no research using a combination of EVT and ML to estimate the investment risk. The results showed that the hybrid model produced better Value-at-Risk (VaR) accuracy under uncertainty and nonlinear conditions. Generally, models only use daily return data as model input. Based on research gaps, a hybrid model framework for estimating risk measures is proposed using a combination of EVT and ML, using multivariable and high-frequency data to identify extreme values in the distribution of data. The goal is to produce an accurate and flexible estimated risk value against extreme changes and shocks in the stock market. Mathematics Subject Classification: 60G25; 62M20; 6245; 62P05; 91G70.
Influence of cultural practices on breast cancer risks, stage at presentation and outcome in a multi-ethnic developing country

Abdullah N, Mohamed N

Oncol Lett, 2021 Nov;22(5):806.
PMID: 34630713 DOI: 10.3892/ol.2021.13067

Malaysia is a developing country made up of three main ethnicities: Malay, Chinese and Indian. There are significant ethnic differences with regard to the type of daily food and cooking methods, contraception, breast-feeding preferences, confinement period and care, postmenopausal intake and influence of the traditional healer. Breast cancer is the most common cancer among Malaysian women across all three ethnicities. However, the National Cancer Registry and local medical centres have documented ethnic differences in breast cancer risk (Chinese, 40.7 per 100,000; Indian, 38.1 per 100,000; Malay, 31.5 per 100,000), peak age (youngest in the Malays), stage at presentation (largest percentage at advanced stage among the Malays) and survival (poorest survival rate among the Malays). The Malays have several practices that are protective against breast cancer compared with the Chinese. However, the Malays have strong beliefs in the traditional healer, which contribute to the delay in getting treatment, causing a poor outcome and a low survival rate. The highest BRCA1 and 2 genetic mutation incidence is amongst the Chinese, but the Malays have the largest triple-negative breast cancer rates. These factors may also contribute to the statistical breast cancer data.
Fulltext Combination of Epicatechin 3-Gallate from Euphorbia hirta and Cefepime Promotes Potential Synergistic Eradication Action against Resistant Clinical Isolate of Pseudomonas aeruginosa

Perumal S, Mahmud R, Mohamed N

Evid Based Complement Alternat Med, 2018;2018:5713703.
PMID: 30108657 DOI: 10.1155/2018/5713703

Pseudomonas aeruginosa is naturally resistant to many classes of antipseudomonal antibiotics due to the species ability to easily acquire resistance. Plant-based antibacterial agent in combination with the existing antibiotic proposes an alternative treatment regimen for the eradication of resistant bacterial infections. The antibacterial effects of the isolated epicatechin 3-gallate compound from Euphorbia hirta in combination with cefepime were investigated in vitro against resistant P. aeruginosa. The fractional inhibitory concentration index of the combination was determined using checkerboard broth microdilution method. Epicatechin 3-gallate combined with cefepime had produced synergistic effect against P. aeruginosa (with average FIC index of 0.24). The MIC of epicatechin 3-gallate was effectively reduced to MIC/4, MIC/8, MIC/16, and MIC/32 in the presence of cefepime. Time-kill study of epicatechin 3-gallate combined with cefepime exhibited remarkable bactericidal activity where the eradication of P. aeruginosa occurred within 4 h of treatment. Scanning electron micrographs revealed apparent cell membrane damage and leakage of cytoplasmic contents from P. aeruginosa cells which eventually led to the cell lysis after the combination treatment of epicatechin 3-gallate and cefepime. The potential of epicatechin 3-gallate to act synergistically with cefepime against clinically resistant P. aeruginosa strain possibly will maximize the successful outcomes when choosing empirical antibiotic treatment in hospitals or health care institutions.
Fulltext Use of medicinal plants and natural products for treatment of osteoporosis and its complications

Soelaiman IN, Das S, Shuid AN, Mo H, Mohamed N

Evid Based Complement Alternat Med, 2013;2013:764701.
PMID: 23476703 DOI: 10.1155/2013/764701
Salmonella enteritidis abdominal aorta mycotic aneurysm presented with acute cholestatic jaundice: A case report and literature review

Wahab AA, Mohamed N, Ding CH, Muttaqillah NAS, Rosli N, Mohammed F

Trop Biomed, 2023 Mar 01;40(1):23-28.
PMID: 37356000 DOI: 10.47665/tb.40.1.008

Mycotic aneurysm is one of the extra-intestinal manifestations of Salmonella Enteritidis infection. The diagnosis of this condition is challenging owed to its variation in clinical presentations. We presented a case of a 54-year-old man with underlying diabetes mellitus and chronic smokers presented with acute right flank pain and fever associated with mild jaundice. The initial laboratory investigations suggested features of obstructive jaundice and urinary tract infection. The contrast enhancing computed tomography of the abdomen revealed the presence of saccular mycotic aneurysm located at the infrarenal abdominal aorta. The blood culture grew Salmonella Enteritidis which was susceptible to ceftriaxone, trimethoprim-sulfamethoxazole, ciprofloxacin, ampicillin, and amoxicillin-clavulanic acid. Intravenous ceftriaxone was initiated, and he underwent open surgery and artery repair at day 8 of admission. He responded well to the treatment given and subsequently discharged home after completed three weeks of intravenous ceftriaxone.

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